| 摘要 |
PURPOSE:To enable cost reduction and the simplification of constitution by suppressing the temp. characteristics of the output voltage of the titled apparatus to a min. degree, by setting the sensitivities of two light receiving elements so that the ratio of the output currents at the lower limit color temp. of the predetermined color temp. range of a light source is equal to the reciprocal of the ratio of the output currents at the upper color temp. CONSTITUTION:A light receiving apparatus 11 is equipped with two first and second light receiving elements 1a, 1b different in spectral characteristics, first and second current/voltage converter means 4a, 4b for respectively converting the output currents of both elements 1a, 1b and a difference signal output means 9 for outputting the difference signal of both voltages. The sensitivities of both elements 1a, 1b are set so that the ratio of the output currents of both elements 1a, 1b at the lower limit color temp. of the predetermined color temp. range of a light source is equal to the reciprocal of the ratio of output currents of both elements 1a, 1b at the upper limit color temp. By this method, the output current ration of both elements 1a, 1b becomes the real output ratio to the change in the color temps. of both elements 1a, 1b and the temp. characteristics of the difference signal outputted from the apparatus 11 become min. |
